[单选题]
The reason the position of ar ;+ 6h5vbdxkn particle c3icec; my4l8q0.i u3r+hjg wtannot be specified with infinite precisio.4u8r0; ewtjl 3ymcc+ihq3 gin is the
A. exclusion principle.
B. uncertainty principle.
C. photoelectric effect.
D. principle of relativity.
